Pottermore, the Harry Potter online experience launched by J K Rowling last year, will go live in early April, having been delayed and in beta mode since October.
In a statement on the Pottermore Insider blog, the company said the delay has been due to switching the site to "an entirely different platform set up".
The statement said the company will be "adding exclusive content and many more exciting features (such as sounds) to Pottermore for you to explore, share and discover".
The site will sell e-books and digital audio versions of the seven Harry Potter books exclusively. A Pottermore spokesman said the shop is likely to open at a “similar time” to the full launch of the site in early April, but the final date is not “totally confirmed as yet”.
The Pottermore Insider statement added: "We always knew Pottermore would be incredibly popular, which is why we made the decision to only open to one million beta users to begin with. We wanted to make sure that we had a really good understanding of how people want to use the site and which bits we’d need to modify before giving more people access.
"We gathered some incredibly useful feedback from our beta users, and it became clear that our original platform wouldn’t be suitable when millions more users came on to the site. So we made a big decision: to move Pottermore to an entirely different platform set up.
"This ‘invisible’ change has involved a lot of work behind the scenes but it will enable our users to get the best from Pottermore as it grows and develops."
At the end of last month, it was announced that OverDrive will be distributing the Harry Potter e-books to school and public libraries worldwide.